Greens still unconvinced on desal plant site

The Greens say there is no new evidence to suggest locating a desalination plant in South Australia's Upper Spencer Gulf would be safe for the giant Australian cuttlefish.

The State Opposition says it is satisfied with BHP Billiton choosing Point Lowly to build the plant and the State Government has said it is also happy with the decision.

However, Greens' MP Mark Parnell says he is still not convinced the area would be safe and the community should continue fighting to have it moved to another location.

"At the end of the day, BHP wants to spend as little as it can on pipelines and they know that it's more expensive to put the desalination plant on the west coast, which is why they're insisting on putting it in Upper Spencer Gulf," he said.

"BHP Billiton have spent a lot of money finding scientists who will say that it's a good location.

"I remain unconvinced and I think there are other scientists in South Australia that are unconvinced that an area like Upper Spencer Gulf is a better location than some places that are further away."

Meanwhile, a Whyalla diver says giant Australian cuttlefish numbers in Upper Spencer Gulf this season are significantly lower than usual.

Hundreds of recreational divers have been travelling to Point Lowly to witness the annual breeding cycle.

However, diver Tony Bramley says there have not been many to see and they are smaller than previous years.

He says the numbers are concerning and fishing should be banned in the surrounding area until the cause is known.

"We can't allow fishing to continue when we don't know how much effect it's having on the aggregation, how detrimental it is," he said.

"We just don't have that information.

"We have an international duty to stop the fishing because stocks are down and we don't know why."

Only a third of the cuttlefish's breeding ground is currently protected and that area will be smaller under proposed State Government marine parks.